Enhanced signaling of extended dependent random-access point supplemental enhancement information

This application is a continuation of International Patent Application No. PCT/CN2022/101412, filed on Jun. 27, 2022, which claims the benefit of International Application No. PCT/CN2021/102636, filed on Jun. 28, 2021. All the aforementioned patent applications are hereby incorporated by reference in their entireties.

The present disclosure relates to generation, storage, and consumption of digital audio video media information in a file format.

Digital video accounts for the largest bandwidth used on the Internet and other digital communication networks. As the number of connected user devices capable of receiving and displaying video increases, the bandwidth demand for digital video usage is likely to continue to grow.

A first aspect relates to a method for processing video data comprising: determining a value of an extended dependent random-access point (EDRAP) leading pictures decodable flag (edrap_leading_pictures_decodable_flag) syntax element; and performing a conversion between a visual media data and a bitstream based on the edrap_leading_pictures_decodable_flag syntax element.

Optionally, in any of the preceding aspects, another implementation of the aspect provides that the bitstream comprises at least one EDRAP picture, and wherein the value of the edrap_leading_pictures_decodable_flag indicates whether ordering constraints are imposed on the EDRAP picture.

Optionally, in any of the preceding aspects, another implementation of the aspect provides that the ordering constraints are not imposed on the EDRAP picture when the value of the edrap_leading_pictures_decodable_flag is zero.

Optionally, in any of the preceding aspects, another implementation of the aspect provides that the ordering constraints are imposed on the EDRAP picture when the value of the edrap_leading_pictures_decodable_flag is one.

Optionally, in any of the preceding aspects, another implementation of the aspect provides that the constraints specify that any picture that is in a same layer as the EDRAP picture and that follows the EDRAP picture in decoding order shall follow, in output order, any other picture that is in the same layer as the EDRAP picture and that precedes the EDRAP picture in decoding order.

Optionally, in any of the preceding aspects, another implementation of the aspect provides that the constraints specify that any picture that is in a same layer as the EDRAP picture, that follows the EDRAP picture in decoding order, and that precedes the EDRAP picture in output order shall not include, in active entries of a reference picture list of the picture, any other picture that is in the same layer as the EDRAP picture and that precedes the EDRAP picture in decoding order, with an exception of a list of referenceable pictures.

Optionally, in any of the preceding aspects, another implementation of the aspect provides that the edrap_leading_pictures_decodable_flag syntax element is included in an EDRAP SEI message.

Optionally, in any of the preceding aspects, another implementation of the aspect provides that the list of referenceable pictures includes Intra Random Access Point (IRAP) or EDRAP pictures in decoding order that are within a same coded layer video sequence (CLVS).

Optionally, in any of the preceding aspects, another implementation of the aspect provides that each picture in the list of referenceable pictures is identified by an i-th EDRAP reference access point identifier (edrap_ref_rap_id[i]) syntax element.

Optionally, in any of the preceding aspects, another implementation of the aspect provides that the edrap_leading_pictures_decodable_flag syntax element is u(v)-coded.

Optionally, in any of the preceding aspects, another implementation of the aspect provides that each EDRAP picture is a trailing picture.

Optionally, in any of the preceding aspects, another implementation of the aspect provides that each EDRAP picture has a temporal sublayer identifier equal to zero.

Optionally, in any of the preceding aspects, another implementation of the aspect provides that each EDRAP picture does not include any pictures in a same layer in active entries of a reference picture list of the EDRAP pictures except the list of referenceable pictures.

Optionally, in any of the preceding aspects, another implementation of the aspect provides that the bitstream is constrained such that any picture that is in a same layer as the EDRAP picture and that follows the EDRAP picture in both decoding order and output order does not include, in active entries of a reference picture list of the picture, any other picture that is in the same layer and precedes the EDRAP picture in decoding order or output order with the exception of the list of referenceable pictures.

Optionally, in any of the preceding aspects, another implementation of the aspect provides that the conversion includes encoding the visual media data into the bitstream.

Optionally, in any of the preceding aspects, another implementation of the aspect provides that the conversion includes decoding the visual media data from the bitstream.

A second aspect relates to an apparatus for processing video data comprising: a processor; and a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to perform the method of any of the preceding aspects.

A third aspect relates to a non-transitory computer readable medium comprising a computer program product for use by a video coding device, the computer program product comprising computer executable instructions stored on the non-transitory computer readable medium such that when executed by a processor cause the video coding device to perform the method of any of the preceding aspects.

A fourth aspect relates to a non-transitory computer-readable recording medium storing a bitstream of a video which is generated by a method performed by a video processing apparatus, wherein the method comprises: determining a value of an extended dependent random-access point (EDRAP) leading pictures decodable flag (edrap_leading_pictures_decodable_flag) syntax element; and generating a bitstream based on the determining

A fifth aspect relates to a method for storing bitstream of a video comprising: determining a value of an extended dependent random-access point (EDRAP) leading pictures decodable flag (edrap_leading_pictures_decodable_flag) syntax element; generating a bitstream based on the determining; and storing the bitstream in a non-transitory computer-readable recording medium.

For the purpose of clarity, any one of the foregoing embodiments may be combined with any one or more of the other foregoing embodiments to create a new embodiment within the scope of the present disclosure.

These and other features will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims

It should be understood at the outset that although an illustrative implementation of one or more embodiments are provided below, the disclosed systems and/or methods may be implemented using any number of techniques, whether currently known or yet to be developed. The disclosure should in no way be limited to the illustrative implementations, drawings, and techniques illustrated below, including the exemplary designs and implementations illustrated and described herein, but may be modified within the scope of the appended claims along with their full scope of equivalents.

The present disclosure is related to image and/or video coding technologies. Specifically, this disclosure is related to signaling of annotated regions, depth representation information, and extended dependent random-access point (EDRAP) indications in supplemental enhancement information (SEI) messages. The examples may be applied individually or in various combinations, for video bitstreams coded by any codec, such as the versatile video coding (VVC) standard and the versatile SEI messages for coded video bitstreams (VSEI) standard.

The present disclosure includes the following abbreviations. Alpha Channel Information (ACI), Adaptation Parameter Set (APS), Access Unit (AU), Coded Layer Video Sequence (CLVS), Coded Layer Video Sequence Start (CLVSS), Cyclic Redundancy Check (CRC), Color Transform Information (CTI), Coded Video Sequence (CVS), Dependent Random Access Point (DRAP), Depth Representation Information (DRI), Extended Dependent Random Access Point (EDRAP), Finite Impulse Response (FIR), Intra Random Access Point (TRAP), Multiview Acquisition Information (MAI), Network Abstraction Layer (NAL), Picture Parameter Set (PPS), Picture Unit (PU), Random Access Skipped Leading (RASL), Region-Wise Packing (RWP), Sample Aspect Ratio (SAR), Sample Aspect Ratio (SAR), Sample Aspect Ratio Information (SARI), Scalability Dimension Information (SDI), Supplemental Enhancement Information (SEI), Step-wise Temporal Sublayer Access (STSA), Video Coding Layer (VCL), Versatile Supplemental Enhancement Information, also known as Rec. ITU-T H.274|ISO/IEC 23002-7, (VSEI), Video Usability Information (VUI), and Versatile Video Coding, also known as Rec. ITU-T H.266|ISO/IEC 23090-3, (VVC).

Video coding standards have evolved primarily through the development of the International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T) and ISO/International Electrotechnical Commission (IEC) standards. The ITU-T produced H.261 and H.263, ISO/IEC produced Motion Picture Experts Group (MPEG)-1 and MPEG-4 Visual, and the two organizations jointly produced the H.262/MPEG-2 Video and H.264/MPEG-4 Advanced Video Coding (AVC) and H.265/ High Efficiency Video Coding (HEVC) standards. Since H.262, the video coding standards are based on the hybrid video coding structure wherein temporal prediction plus transform coding are utilized. To explore the further video coding technologies beyond HEVC, the Joint Video Exploration Team (JVET) was founded by Video Coding Experts Group (VCEG) and MPEG jointly. Many methods have been adopted by JVET and put into the reference software named Joint Exploration Model (JEM). The JVET was later renamed to be the Joint Video Experts Team (JVET) when the Versatile Video Coding (VVC) project officially started. VVC is a coding standard targeting a 50% bitrate reduction as compared to HEVC. VVC has been finalized by the JVET.

The VVC standard, also known as ITU-T H.266|ISO/IEC 23090-3, and the associated Versatile Supplemental Enhancement Information (VSEI) standard, also known as ITU-T H.274|ISO/IEC 23002-7, are designed for use in a broad range of applications, such as television broadcast, video conferencing, playback from storage media, adaptive bit rate streaming, video region extraction, composition and merging of content from multiple coded video bitstreams, multiview video, scalable layered coding, and viewport-adaptive three hundred sixty degree)(360° immersive media. The Essential Video Coding (EVC) standard (ISO/IEC 23094-1) is another video coding standard developed by MPEG.

An example amendment to the VSEI standard includes the specification of additional SEI messages including an annotated regions SEI message, an alpha channel information SEI message, a depth representation information SEI message, a multiview acquisition information SEI message, a scalability dimension information SEI message, an extended dependent random-access point (DRAP) indication SEI message, a display orientation SEI message, and a colour transform information SEI message.

An example annotated regions SEI message syntax is as follows.

De- scriptor annotated_regions( payloadSize ) {  ar_cancel_flag u(1)  if( !ar_cancel_flag ) {   ar_not_optimized_for_viewing_flag u(1)   ar_true_motion_flag u(1)   ar_occluded_object_flag u(1)   ar_partial_object_flag_present_flag u(1)   ar_object_label_present_flag u(1)   ar_object_confidence_info_present_flag u(1)   if( ar_object_confidence_info_present_flag )    ar_object_confidence_length_minus1 u(4)   if( ar_object_label_present_flag ) {    ar_object_label_language_present_flag u(1)    if( ar_object_label_language_present_flag ) {     while( !byte_aligned( ) )      ar_bit_equal_to_zero /* equal to 0 */ f(1)     ar_object_label_language st(v)    }    ar_num_label_updates ue(v)    for( i = 0; i < ar_num_label_updates; i++ ) {     ar_label_idx[ i ] ue(v)     ar_label_cancel_flag u(1)     LabelAssigned[ ar_label_idx[ i ] ] =    !ar_label_cancel_flag     if( !ar_label_cancel_flag ) {      while( !byte_aligned( ) )       ar_bit_equal_to_zero /* equal to 0 */ f(1)      ar_label[ ar_label_idx[ i ] ] st(v)     }    }   }   ar_num_object_updates ue(v)   for( i = 0; i <= ar_num_object_updates; i++ ) {    ar_object_idx[ i ] ue(v)    ar_object_cancel_flag u(1)    ObjectTracked[ ar_object_idx[ i ] ] =    !ar_object_cancel_flag    if( !ar_object_cancel_flag ) {     if( ar_object_label_present_flag ) {      ar_object_label_update_flag u(1)      if( ar_object_label_update_flag )       ar_object_label_idx[ ar_object_idx[ i ] ] ue(v)     }     ar_bounding_box_update_flag u(1)     if( ar_bounding_box_update_flag ) {      ar_bounding_box_cancel_flag u(1)      ObjectBoundingBoxAvail[ ar_object_idx[ i ] ] =        !ar_bounding_box_cancel_flag      if( !ar_bounding_box_cancel_flag ) {       ar_bounding_box_top[ ar_object_idx[ i ] ] u(16)       ar_bounding_box_left[ ar_object_idx[ i ] ] u(16)       ar_bounding_box_width[ ar_object_idx[ i ] ] u(16)       ar_bounding_box_height[ ar_object_idx[ i ] ] u(16)       if( ar_partial_object_flag_present_flag )        ar_partial_object_flag[ ar_object_idx[ i ] ] u(1)       if( ar_object_confidence_info_present_flag )        ar_object_confidence[ ar_object_idx[ i ] ] u(v)      }     }    }   }  } }

An example annotated regions SEI message semantics is as follows. The annotated regions SEI message carries parameters that identify annotated regions using bounding boxes representing the size and location of identified objects. Use of this SEI message may require the definition of the following variables. Such variables include a cropped picture width and picture height in units of luma samples, denoted herein by CroppedWidth and CroppedHeight, respectively; a chroma sub-sampling width and height, denoted as SubWidthC and SubHeightC, respectively; a conformance cropping window left offset denoted as ConfWinLeftOffset; and a conformance cropping window top offset, denoted as ConfWinTopOffset.

An ar_cancel_flag set equal to 1 indicates that the annotated regions SEI message cancels the persistence of any previous annotated regions SEI message that is associated with one or more layers to which the annotated regions SEI message applies. An ar_cancel_flag set equal to 0 indicates that annotated regions information follows. When ar_cancel_flag is equal to 1 or a new CVS of the current layer begins, the variables LabelAssigned[i], ObjectTracked[i], and ObjectBoundingBoxAvail are set equal to 0 for i in the range of 0 to 255, inclusive.

An ar_not_optimized_for_viewing_flag set equal to 1 indicates that the decoded pictures that the annotated regions SEI message applies to are not optimized for user viewing, but rather are optimized for some other purpose such as algorithmic object classification performance. An ar_not_optimized_for_viewing_flag set equal to 0 indicates that the decoded pictures that the annotated regions SEI message applies to may or may not be optimized for user viewing.

An ar_true_motion_flag set equal to 1 indicates that the motion information in the coded pictures that the annotated regions SEI message applies to was selected with a goal of accurately representing object motion for objects in the annotated regions. An ar_true_motion_flag set equal to 0 indicates that the motion information in the coded pictures that the annotated regions SEI message applies to may or may not be selected with a goal of accurately representing object motion for objects in the annotated regions.

An ar_occluded_object_flag set equal to 1 indicates that the ar_bounding_box_top[ar_object_idx[i]], ar_bounding_box_left[ar_object_idx[i]], ar_bounding_box_width[ar_object_idx[i]], and ar_bounding_box_height[ar_object_idx[i]] syntax elements each represent the size and location of an object or a portion of an object that may not be visible or may be only partially visible within the cropped decoded picture. An ar_occluded_object_flag set equal to 0 indicates that the ar_bounding_box_top[ar_object_idx[i]], ar_bounding_box_left[ar_object_idx[i]], ar_bounding_box_width[ar_object_idx[i]], and ar_bounding_box_height[ar_object_idx[i]] syntax elements represent the size and location of an object that is entirely visible within the cropped decoded picture. Bitstream conformance may require that the value of ar_occluded_object_flag shall be the same for all annotated_regions( ) syntax structures within a CVS.

An ar_partial_object_flag_present_flag set equal to 1 indicates that ar_partial_object_flag[ar_object_idx[i]] syntax elements are present. An ar_partial_object_flag_present_flag set equal to 0 indicates that ar_partial_object_flag [ar_object_idx[i]] syntax elements are not present. Bitstream conformance may require that the value of ar_partial_object_flag_present_flag shall be the same for all annotated_regions( ) syntax structures within a CVS.

An ar_object_label_present_flag set equal to 1 indicates that label information corresponding to objects in the annotated regions is present. An ar_object_label_present_flag set equal to 0 indicates that label information corresponding to the objects in the annotated regions is not present.

An ar_object_confidence_info_present_flag set equal to 1 indicates that ar_object_confidence [ar_object_idx[i]] syntax elements are present. An ar_object_confidence_info_present_flag set equal to 0 indicates that ar_object_confidence[ar_object_idx[i]] syntax elements are not present. Bitstream conformance may require that the value of ar_object_confidence_present_flag shall be the same for all annotated_regions( )syntax structures within a CVS.

An ar_object_confidence_length_minus1+1 specifies the length, in bits, of the ar_object_confidence[ar_object_idx[i]] syntax elements. Bitstream conformance may require that the value of ar_object_confidence_length_minus1 shall be the same for all annotated_regions( ) syntax structures within a CVS.

An ar_object_label_language_present_flag set equal to 1 indicates that the ar_object_label_language syntax element is present. An ar_object_label_language_present_flag set equal to 0 indicates that the ar_object_label_language syntax element is not present. An ar_bit_equal_to_zero shall be equal to zero.

An ar_object_label_language contains a language tag followed by a null termination byte equal to 0×00. The length of the ar_object_label_language syntax element shall be less than or equal to 255 bytes, not including the null termination byte. When not present, the language of the label is unspecified.

An ar_num_label_updates indicates the total number of labels associated with the annotated regions that will be signaled. The value of ar_num_label_updates shall be in the range of 0 to 255, inclusive. An ar_label_idx[i] indicates the index of the signaled label. The value of ar_label_idx[i] shall be in the range of 0 to 255, inclusive.

An ar_label_cancel_flag set equal to 1 cancels the persistence scope of the ar_label_idx[i]-th label. An ar_label_cancel_flag set equal to 0 indicates that the ar_label_idx[i]-th label is assigned a signaled value. An ar_label[ar_label_idx[i]] specifies the contents of the ar_label_idx[i]-label. The length of the ar_label[ar_label_idx[i]] syntax element shall be less than or equal to 255 bytes, not including the null termination byte.

An ar_num_object_updates indicates the number of object updates to be signaled. An ar_num_object_updates shall be in the range of 0 to 255, inclusive. An ar_object_idx[i] is the index of the object parameters signaled. An ar_object_idx[i] shall be in the range of 0 to 255, inclusive. An ar_object_cancel_flag set equal to 1 cancels the persistence scope of the ar_object_idx[i]-th object. An ar_object_cancel_flag set equal to 0 indicates that parameters associated with the ar_object_idx[i]-th object tracked object will be signaled. An ar_object_label_update_flag set equal to 1 indicates that an object label is signaled. An ar_object_label_update_flag equal to 0 indicates that an object label is not signaled.

An ar_object_label_idx[ar_object_idx[i]] indicates the index of the label corresponding to the ar_object_idx[i]-th object. When an ar_object_label_idx[ar_object_idx[i]] is not present, its value is inferred from a previous annotated regions SEI messages in output order in the same CVS, if any. An ar_bounding_box_update_flag set equal to 1 indicates that object bounding box parameters are signaled. An ar_bounding_box_update_flag set equal to 0 indicates that object bounding box parameters are not signaled.

An ar_bounding_box_cancel_flag set equal to 1 cancels the persistence scope of the ar_bounding_box_top[ar_object_idx[i]], ar_bounding_box_left[ar_object_idx[i]], ar_bounding_box_width[ar_object_idx[i]], ar_bounding_box_height[ar_object_idx[i]], ar_partial_object_flag[ar_object_idx[i]], and ar_object_confidence[ar_object_idx[i]]. An ar_bounding_box_cancel_flag set equal to 0 indicates that ar_bounding_box_top [ar_object_idx[i]], ar_bounding_box_left[ar_object_idx[i]], ar_bounding_box_width [ar_object_idx[i]] ar_bounding_box_height[ar_object_idx[i]] ar_partial_object_flag [ar_object_idx[i]], and ar_object_confidence[ar_object_idx[i]] syntax elements are signaled.

An ar_bounding_box_top[ar_object_idx[i]], ar_bounding_box_left[ar_object_idx [i]], ar_bounding_box_width[ar_object_idx[i]], and ar_bounding_box_height[ar_object_idx [i]] specify the coordinates of the top-left corner and the width and height, respectively, of the bounding box of the ar_object_idx[i]-th object in the cropped decoded picture, relative to the conformance cropping window specified by the active SPS.

The value of ar_bounding_box_left[ar_object_idx[i]] shall be in the range of 0 to CroppedWidth/SubWidthC−1, inclusive. The value of ar_bounding_box_top[ar_object_idx[i]] shall be in the range of 0 to CroppedHeight/SubHeightC−1, inclusive. The value of ar_bounding_box_width[ar_object_idx[i]] shall be in the range of 0 to CroppedWidth/SubWidthC-ar_bounding_box_left[ar_object_idx[i]], inclusive. The value of ar_bounding_box_height[ar_object_idx[i]] shall be in the range of 0 to CroppedHeight/SubHeightC-ar_bounding_box_top[ar_object_idx[i]], inclusive. The identified object rectangle contains the luma samples with horizontal picture coordinates from SubWidthC*(ConfWinLeftOffset+ar_bounding_box_left[ar_object_idx[i]]) to SubWidthC*(ConfWinLeftOffset+ar_bounding_box_left[ar_object_idx[i]]+ar_bounding_box_width [ar_object_idx[i]])−1, inclusive, and vertical picture coordinates from SubHeightC*(ConfWinTopOffset+ar_bounding_box_top[ar_object_idx[i]]) to SubHeightC*(ConfWinTopOffset+ar_bounding_box_top[ar_object_idx[i]]+ar_bounding_box_height [ar_object_idx[i]])−1, inclusive. The values of ar_bounding_box_top[ar_object_idx[i]], ar_bounding_box_left[ar_object_idx[i]], ar_bounding_box_width[ar_object_idx[i]] and ar_bounding_box_height[ar_object_idx[i]] persist in output order within the CVS for each value of ar_object_idx[i]. When not present, the values of ar_bounding_box_top[ar_object_idx[i]], ar_bounding_box_left[ar_object_idx[i]], ar_bounding_box_width[ar_object_idx[i]] or ar_bounding_box_height[ar_object_idx[i]] are inferred from a previous annotated regions SEI message in output order in the CVS, if any.

An ar_partial_object_flag[ar_object_idx[i]]set equal to 1 indicates that the ar_bounding_box_top[ar_object_idx[i]], ar_bounding_box_left[ar_object_idx[i]], ar_bounding_box_width[ar_object_idx[i]] and ar_bounding_box_height[ar_object_idx[i]]syntax elements represent the size and location of an object that is only partially visible within the cropped decoded picture. An ar_partial_object_flag[ar_object_idx[i]] set equal to 0 indicates that the ar_bounding_box_top[ar_object_idx[i]], ar_bounding_box_left[ar_object_idx[i]], ar_bounding_box_width[ar_object_idx[i]] and ar_bounding_box_height[ar_object_idx[i]] syntax elements represent the size and location of an object that may or may not be only partially visible within the cropped decoded picture. When not present, the value of ar_partial_object_flag[ar_object_idx[i]] is inferred from a previous annotated regions SEI message in output order in the CVS, if any.

An ar_object_confidence[ar_object_idx[i]] indicates the degree of confidence associated with the ar_object_idx[i]-th object, in units of 2−(ar_object_confidence_length_minus1+1), such that a higher value of ar_object_confidence[ar_object_idx[i]] indicates a higher degree of confidence. The length of the ar_object_confidence[ar_object_idx[i]] syntax element is ar_object_confidence_length_minus1+1 bits. When not present, the value of object_confidence[ar_object_idx[i]] is inferred from a previous annotated regions SEI message in output order in the CVS, if any.

A depth representation information SEI message is now discussed. An example depth representation information SEI message syntax is as follows.

De- scriptor depth_representation_info( payloadSize ) {  z_near_flag u(1)  z_far_flag u(1)  d_min_flag u(1)  d_max_flag u(1)  depth_representation_type ue(v)  if( d_min_flag | | d_max_flag )   disparity_ref_view_id ue(v)  if( z_near_flag )   depth_rep_info_element( ZNearSign, ZNearExp, ZNearMantissa, ZNearManLen )  if( z_far_flag )   depth_rep_info_element( ZFarSign, ZFarExp,   ZFarMantissa, ZFarManLen )  if( d_min_flag )   depth_rep_info_element( DMinSign, DMinExp, DMinMantissa, DMinManLen )  if( d_max_flag )   depth_rep_info_element( DMaxSign, DMaxExp, DMaxMantissa, DMaxManLen )  if( depth_representation_type = = 3 ) {   depth_nonlinear_representation_num_minus1 ue(v)   for( i = 1; i <=   depth_nonlinear_representation_num_minus1 + 1; i++ )    depth_nonlinear_representation_model[ i ]  } }

An example depth representation information element syntax is as follows.

Descriptor depth_rep_info_element( OutSign, OutExp, OutMantissa, OutManLen ) {  da_sign_flag u(1)  da_exponent u(7)  da_mantissa_len_minus1 u(5)  da_mantissa u(v) }

An example depth representation information SEI message semantics is as follows. The syntax elements in the depth representation information (DRI) SEI message specify various parameters for auxiliary pictures of type AUX_DEPTH for the purpose of processing decoded primary and auxiliary pictures prior to rendering on a three-dimensional (3D) display, such as view synthesis. For example, depth or disparity ranges for depth pictures are specified.

Use of this SEI message may requires the definition of the following variable. A bit depth for the samples of the luma component, denoted herein by BitDepthY. When a CVS does not contain an SDI SEI message with sdi_aux_id[i] equal to 2 for at least one value of i, no picture in the CVS shall be associated with a DRI SEI message. When an access unit (AU) contains both an SDI SEI message with sdi_aux_id[i] equal to 2 for at least one value of i and a DRI SEI message, the SDI SEI message shall precede the DRI SEI message in decoding order. When present, the DRI SEI message shall be associated with one or more layers that are indicated as depth auxiliary layers by an SDI SEI message. The following semantics apply separately to each nuh_layer_id targetLayerId among the nuh_layer_id values to which the DRI SEI message applies. When present, the DRI SEI message may be included in any access unit. It is recommended that, when present, the SEI message is included for the purpose of random access in an access unit in which the coded picture with nuh_layer_id equal to targetLayerId is an TRAP picture. The information indicated in the DRI SEI message applies to all the pictures with nuh_layer_id equal to targetLayerId from the access unit containing the SEI message up to but excluding the next picture, in decoding order, associated with a DRI SEI message applicable to targetLayerId or to the end of the CLVS of the nuh_layer_id equal to targetLayerId, whichever is earlier in decoding order.

A z_near_flag set equal to 0 specifies that the syntax elements specifying the nearest depth value are not present in the syntax structure. A z_near_flag set equal to 1 specifies that the syntax elements specifying the nearest depth value are present in the syntax structure. A z_far_flag set equal to 0 specifies that the syntax elements specifying the farthest depth value are not present in the syntax structure. A z_far_flag set equal to 1 specifies that the syntax elements specifying the farthest depth value are present in the syntax structure. A d_min_flag set equal to 0 specifies that the syntax elements specifying the minimum disparity value are not present in the syntax structure. A d_min_flag set equal to 1 specifies that the syntax elements specifying the minimum disparity value are present in the syntax structure. A d_max_flag set equal to 0 specifies that the syntax elements specifying the maximum disparity value are not present in the syntax structure. A d_max_flag set equal to 1 specifies that the syntax elements specifying the maximum disparity value are present in the syntax structure. A depth_representation_type specifies the representation definition of decoded luma samples of auxiliary pictures as specified in Table 1. In Table 1, disparity specifies the horizontal displacement between two texture views and Z value specifies the distance from a camera. The variable maxVal is set equal to (1«BitDepthY)−1.

TABLE 1 Definition of depth_representation_type depth_representation_type Interpretation 0 Each decoded luma sample value of an auxiliary picture represents an inverse of Z value that is uniformly quantized into the range of 0 to maxVal, inclusive. When z_far_flag is equal to 1, the luma sample value equal to 0 represents the inverse of ZFar (specified below). When z_near_flag is equal to 1, the luma sample value equal to maxVal represents the inverse of ZNear (specified below). 1 Each decoded luma sample value of an auxiliary picture represents disparity that is uniformly quantized into the range of 0 to maxVal, inclusive. When d_min_flag is equal to 1, the luma sample value equal to 0 represents DMin (specified below). When d_max_flag is equal to 1, the luma sample value equal to maxVal represents DMax (specified below). 2 Each decoded luma sample value of an auxiliary picture represents a Z value uniformly quantized into the range of 0 to maxVal, inclusive. When z_far_flag is equal to 1, the luma sample value equal to 0 corresponds to ZFar (specified below). When z_near_flag is equal to 1, the luma sample value equal to maxVal represents ZNear (specified below). 3 Each decoded luma sample value of an auxiliary picture represents a nonlinearly mapped disparity, normalized in range from 0 to maxVal, as specified by depth_nonlinear_representation_num_minus1 and depth_nonlinear_representation_model[ i ]. When d_min_flag is equal to 1, the luma sample value equal to 0 represents DMin (specified below). When d_max_flag is equal to 1, the luma sample value equal to maxVal represents DMax (specified below). Other values Reserved for future use

A disparity_ref_view_id specifies the ViewId value against which the disparity values are derived. It should be noted that disparity_ref_view_id is present only if d_min_flag is equal to 1 or d_max_flag is equal to 1 and is useful for depth_representation_type values equal to 1 and 3. The variables in the x column of Table 2 are derived from the respective variables in the s, e, n and v columns of Table 2 as follows. If the value of e is in the range of 0 to 127, exclusive, x is set equal to (−1)s*2e−31*(1+n÷2v). Otherwise (e is equal to 0), x is set equal to (−1)s*2−(30+v)*n.

TABLE 2 Association between depth parameter variables and syntax elements x s e n v ZNear ZNearSign ZNearExp ZNearMantissa ZNearManLen ZFar ZFarSign ZFarExp ZFarMantissa ZFarManLen DMax DMaxSign DMaxExp DMaxMantissa DMaxManLen DMin DMinSign DMinExp DMinMantissa DMinManLen

The DMin and DMax values, when present, are specified in units of a luma sample width of the coded picture with Viewld equal to Viewld of the auxiliary picture. The units for the ZNear and ZFar values, when present, are identical but unspecified. A depth_nonlinear_representation_num_minus 1 plus 2 specifies the number of piece-wise linear segments for mapping of depth values to a scale that is uniformly quantized in terms of disparity. A depth_nonlinear_representation_model[i] for i ranging from 0 to depth_nonlinear_representation_num_minus1+2, inclusive, specify the piece-wise linear segments for mapping of decoded luma sample values of an auxiliary picture to a scale that is uniformly quantized in terms of disparity. The values of depth_nonlinear_representation_model1[0] and depth_nonlinear_representation_model[depth_nonlinear_representation_num_minus1+2] are both inferred to be equal to 0.

When depth_representation_type is equal to 3, an auxiliary picture contains nonlinearly transformed depth samples. The variable DepthLUT[i], as specified below, is used to transform decoded depth sample values from the nonlinear representation to the linear representation, e.g., uniformly quantized disparity values. The shape of this transform is defined by a line-segment approximation in two-dimensional linear-disparity-to-nonlinear-disparity space. The first (0, 0) and the last (maxVal, maxVal) nodes of the curve are predefined. Positions of additional nodes are transmitted in form of deviations (depth_nonlinear_representation_model[i]) from the straight-line curve. These deviations are uniformly distributed along the whole range of 0 to maxVal, inclusive, with spacing depending on the value of nonlinear_depth_representation_num_minus1.

The variable DepthLUT[i] for i in the range of 0 to maxVal, inclusive, is specified as follows:

for( k = 0; k <= depth_nonlinear_representation_num_minus1 + 1; k++ ) {  pos1 = ( maxVal * k ) /  (depth_nonlinear_representation_num_minus1 + 2 )  dev1 = depth_nonlinear_representation_model[ k ]  pos2 = ( maxVal * ( k + 1 ) ) /  (depth_nonlinear_representation_num_minus1 + 2 )  dev2 = depth_nonlinear_representation_model[ k + 1 ] (X)  x1 = pos1 − dev1  y1 = pos1 + dev1  x2 = pos2 − dev2  y2 = pos2 + dev2  for( x = Max( x1, 0 ); x <= Min( x2, maxVal ); x++ )   DepthLUT[ x ] = Clip3( 0, maxVal, Round( ( ( x − x1 ) * ( y2 −   y1 ) ) ÷ ( x2 − x1 ) + y1 ) ) }

When depth_representation_type is equal to 3, DepthLUT[dS] for all decoded luma sample values dS of an auxiliary picture in the range of 0 to maxVal, inclusive, represents disparity that is uniformly quantized into the range of 0 to maxVal, inclusive.

Depth representation information element semantics are as follows. The syntax structure specifies the value of an element in the DRI SEI message. The syntax structure sets the values of the OutSign, OutExp, OutMantissa and OutManLen variables that represent a floating-point value. When the syntax structure is included in another syntax structure, the variable names OutSign, OutExp, OutMantissa and OutManLen are to be interpreted as being replaced by the variable names used when the syntax structure is included.

A da_sign_flag set equal to 0 indicates that the sign of the floating-point value is positive. A da_sign_flag set equal to 1 indicates that the sign is negative. The variable OutSign is set equal to da_sign_flag. A da_exponent specifies the exponent of the floating-point value. The value of da_exponent shall be in the range of 0 to 27−2, inclusive. The value 27−1 is reserved. Decoders shall treat the value 27−1 as indicating an unspecified value. The variable OutExp is set equal to da_exponent. A da_mantissa_len_minus1 plus 1 specifies the number of bits in the da_mantissa syntax element. The value of da_mantissa_len_minus1 shall be in the range of 0 to 31, inclusive. The variable OutManLen is set equal to da_mantissa_len_minus1+1. A da_mantissa specifies the mantissa of the floating-point value. The variable OutMantissa is set equal to da_mantissa.

An extended DRAP indication SEI message is as follows. An example extended DRAP indication SEI message syntax is as follows.

Descriptor extended_drap_indication( payloadSize ) {  edrap_rap_id_minsu1 u(16)  edrap_leading_pictures_decodable_flag u(1)  edrap_reserved_zero_12bits u(12)  edrap_num_ref_rap_pics_minus1 u(3)  for( i= 0; i <= edrap_num_ref_rap_pics_minus1; i++ )   edrap_ref_rap_id[ i ] u(16) }

An example extended DRAP indication SEI message semantics is as follows. The picture associated with an extended DRAP (EDRAP) indication SEI message is referred to as an EDRAP picture. The presence of the EDRAP indication SEI message indicates that the constraints on picture order and picture referencing specified in this subclause apply. These constraints can enable a decoder to properly decode the EDRAP picture and the pictures that are in the same layer and follow it in both decoding order and output order without needing to decode any other pictures in the same layer except the list of pictures referenceablePictures. This includes a list of TRAP or EDRAP pictures in decoding order that are within the same CLVS and identified by the edrap_ref_rapid[i] syntax elements.

The constraints indicated by the presence of the EDRAP indication SEI message, which shall all apply, are as follows. The EDRAP picture is a trailing picture. The EDRAP picture has a temporal sublayer identifier equal to 0. The EDRAP picture does not include any pictures in the same layer in the active entries of its reference picture lists except the referenceablePictures. Any picture that is in the same layer and follows the EDRAP picture in both decoding order and output order does not include, in the active entries of its reference picture lists, any picture that is in the same layer and precedes the EDRAP picture in decoding order or output order, with the exception of the referenceablePictures.

When edrap_leading_pictures_decodable_flag is equal to 1, the following applies. Any picture that is in the same layer and follows the EDRAP picture in decoding order shall follow, in output order, any picture that is in the same layer and precedes the EDRAP picture in decoding order. Any picture that is in the same layer and follows the EDRAP picture in decoding order and precedes the EDRAP picture in output order does not include, in the active entries of its reference picture lists, any picture that is in the same layer and precedes the EDRAP picture in decoding order, with the exception of the referenceablePictures. Any picture in the list referenceablePictures does not include, in the active entries of its reference picture lists, any picture that is in the same layer and is not a picture at an earlier position in the list referenceablePictures. Consequently, the first picture in referenceablePictures, even when it is an EDRAP picture instead of an TRAP picture, does not include any picture from the same layer in the active entries of its reference picture lists.

An edrap_rap_id_minus1 plus 1 specifies the random-access point (RAP) picture identifier, denoted as RapPicId, of the EDRAP picture. Each TRAP or EDRAP picture is associated with a RapPicId value. The RapPicId value for an IRAP picture is inferred to be equal to 0. The RapPicId values for any two EDRAP pictures associated with the same IRAP picture shall be different. An edrap_reserved_zero_12bits shall be equal to 0 in bitstreams conforming to this disclosure. Other values for edrap_reserved_zero_12bits are reserved. Decoders may ignore the value of edrap_reserved_zero_12bits. An edrap_num_ref rap_pics_minus1 plus 1 indicates the number of IRAP or EDRAP pictures that are within the same CLVS as the EDRAP picture and may be included in the active entries of the reference picture lists of the EDRAP picture. An edrap_ref_rapid[i] indicates a RapPicId of the i-th RAP picture that may be included in the active entries of the reference picture lists of the EDRAP picture. The i-th RAP picture shall be either the TRAP picture associated with the current EDRAP picture or an EDRAP picture associated with the same TRAP picture as the current EDRAP picture.

The following are example technical problems solved by disclosed technical solutions. Example designs for the annotated regions SEI message, the depth representation information SEI message, and the EDRAP indication SEI message have at least the following problems. For the annotated regions SEI message, the value range of the ue(v)-coded syntax element AR object label index of an i-th annotated region object index (ar_object_label_idx[ar_object_idx[i]]) is missing. One practical problem associated with having no value range specified for a ue(v)-coded syntax element is that a design may be unsure how many bits can be used for the corresponding variable in an implementation. If the maximum number of bits used value in the implementation is not sufficient, a decoder may crash when encountering a value that is greater than the maximum value allowed by the number of bits used. For the depth representation information SEI message, the descriptor (e.g., the coding method) of the i-th depth nonlinear representation model (depth_nonlinear_representation_model[i]) syntax element is unspecified. Without specifying the coding method, the decoder may not be able to determine how to parse the syntax element. For the depth representation information SEI message, the value ranges for the ue(v)-coded syntax elements depth representation type (depth_representation_type), disparity reference view identifier (disparity_ref_view_id), depth nonlinear representation number minus one (depth_nonlinear_representation_num_minus1), and depth_nonlinear_representation_model[i] are not specified. For the EDRAP indication SEI message, the semantics of the EDRAP leading pictures decodable flag (edrap_leading_pictures_decodable_flag) syntax element is missing.

Disclosed herein are mechanisms to address one or more of the problems listed above. For example, the present disclosure specifies example value ranges for ar_object_label_idx[ar_object_idx[i]]. Further, the present disclosure specifies example descriptors for depth_nonlinear_representation_model[i]. In addition, the present disclosure specifies example value ranges for depth_representation_type, disparity_ref_view_id, depth_nonlinear_representation_num_minus1, and depth_nonlinear_representation_model[i]. In addition, the present disclosure specifies example semantics for edrap_leading_pictures_decodable_flag.

1 FIG. 100 100 100 100 is a schematic diagram illustrating an example bitstream. The bitstreammay include compressed video and related syntax. For example, the bitstreammay be encoded by an encoder, transmitted across one or more networks, and decoded by a decoder for display to a user. For example, a bitstreammay be defined as a sequence of bits that forms a representation of a sequence of access units (AUs) forming one or more coded video sequences (CVSs). An AU is a set of one or more pictures that are associated with a corresponding output time in a video sequence. A bitstream may take the form of a network abstraction layer (NAL) unit stream or a byte stream.

100 135 115 125 131 133 135 113 100 113 113 113 115 115 115 115 115 115 The bitstreamincludes one or more sequence parameter sets (SPSs), a plurality of picture parameter sets (PPS s), a plurality of slices, an annotated region (AR) SEI message, a DRI SEI message, and an EDRAP indications SEI message. An SPScontains sequence data related parameters common to all pictures in a coded video sequence contained in the bitstream. The parameters in a SPScan include picture sizing, bit depth, coding tool parameters, bit rate restrictions, etc. It should be noted that, while each sequence refers to a SPS, a single SPScan contain data for multiple sequences in some examples. The PPScontains parameters that apply to an entire picture. Hence, each picture in the video sequence may refer to a PPS. It should be noted that, while each picture refers to a PPS, a single PPScan contain data for multiple pictures in some examples. For example, multiple similar pictures may be coded according to similar parameters. In such a case, a single PPSmay contain data for such similar pictures. The PPScan indicate coding tools available for slices in corresponding pictures, quantization parameters, offsets, etc.

100 125 The slices each contain a slice header and image data from a region in a picture. The slice header contains parameters that are specific to each slice. Hence, there may be one slice header per slice in the video sequence. The slice header may contain slice type information, picture order counts (POCs), reference picture lists, prediction weights, tile entry points, deblocking parameters, etc. It should be noted that in some examples, a bitstreammay also include a picture header, which is a syntax structure that contains parameters that apply to all slices in a single picture. For this reason, a picture header and a slice header may be used interchangeably in some contexts. For example, certain parameters may be moved between the slice header and a picture header depending on whether such parameters are common to all slices in a picture. The image data in the slicecontains video data encoded according to inter-prediction and/or intra-prediction as well as corresponding transformed and quantized residual data. The video data from one or more slices can be coded from a picture by an encoder and decoded at a decoder to reconstruct the picture.

125 125 125 A slicemay be defined as an integer number of complete tiles or an integer number of consecutive complete coding tree unit (CTU) rows (e.g., within a tile) of a picture, where the tiles or CTU rows are exclusively contained in a single NAL unit. Hence, the sliceis also contained in a single NAL unit. The slicesare each further divided into CTUs and/or coding tree blocks (CTBs). A CTU is a group of samples of a predefined size that can be partitioned by a coding tree. A CTB is a subset of a CTU and contains luma components or chroma components of the CTU. The CTUs/CTBs are further divided into coding blocks based on coding trees. The coding blocks can then be encoded/decoded according to prediction mechanisms.

100 100 131 133 135 The bitstreamcan include one or more SEI messages. A SEI message is a syntax structure with specified semantics that conveys information that is not needed by the decoding process in order to determine the values of the samples in decoded pictures. The bitstreamcan include many different SEI messages for different functionality. In the present example, the bitstream includes an AR SEI message, a DRI SEI message, and an EDRAP indications SEI message.

131 131 131 131 141 141 141 An AR SEI messageis an SEI message that carries parameters to identify annotated regions in one or more pictures by employing bounding boxes. The bounding boxes represent a size and a location of an annotated region and identifies one or more objects contained in the annotated region. Accordingly, the AR SEI messagecontains metadata that describes regions in pictures. The decoder may use the AR SEI messageto determine whether to decode and/or how to treat such regions during the display process. The AR SEI messageincludes an ar_object_label_idx[ar_object_idx[i]]syntax element. The ar_object_label_idx[ar_object_idx[i]]indicates an index of a label corresponding to an i-th indexed AR object (ar_object_idx[i]-th) object. For example, AR objects are indexed and any i-th AR object can be determined by ar_object_idx[i]. Further, AR object labels are indexed and any i-th AR object label can be determined by ar_object_label_idx[i]. As such, the AR SEI ar_object_label_idx[ar_object_idx[i]]obtains the index of the label of the i-th AR object.

133 133 142 143 144 145 142 143 143 142 144 144 145 145 A DRI SEI messageis an SEI message that carries parameters for pictures that contain depth and/or disparity information for rendering on a three dimensional (3D) display. Depth is a location of a pixel/sample in 3D space. Disparity is a displacement between locations of two features (e.g., two pixels) in an image plane. The DRI SEI messagecontains a depth_nonlinear_representation_model [i]syntax element, depth_nonlinear_representation_num_minus1syntax element, a depth_representation_typesyntax element, and a disparity_ref_view_idsyntax element. The depth_nonlinear_representation_model [i]specifies each of i piece-wise linear segments for mapping decoded luma sample values (e.g., depth values) of an auxiliary picture to a scale that is uniformly quantized in terms of disparity. The depth_nonlinear_representation_num_minus1plus two specifies the number of piece-wise linear segments for mapping of depth values to a scale that is uniformly quantized in terms of disparity. Accordingly, the depth_nonlinear_representation_num_minus1plus two specifies the number of i segments in the depth_nonlinear_representation_model[i]. The depth_representation_typespecifies a representation definition of decoded luma samples of auxiliary pictures. The permissible values for depth_representation_typeand a corresponding interpretation of each value is included in table 1 above and/or table Y1 below. The disparity_ref_view_idspecifies a view identifier (ViewId) value against which the disparity values are derived. Accordingly, the disparity_ref_view_idindicates a ViewId value used as a reference when determining disparity (e.g., displacement and/or difference between locations) for samples in an auxiliary picture.

135 135 135 146 135 An EDRAP indications SEI messageindicates usage of EDRAP pictures. An EDRAP picture is a random access picture that is coded by inter prediction based on one or more reference pictures. For example, an EDRAP picture can be coded by reference to a preceding EDRAP picture and/or a preceding TRAP picture. An TRAP picture is coded by intra prediction and can be decoded without reference to other pictures. EDRAP schemes may employ an external bitstream that contains a timed set of reference pictures for each of the EDRAP pictures. In this way, an EDRAP picture can be selected for random access into the main bitstream, and the reference pictures used to decode the EDRAP picture can be obtained from the external bitstream. The EDRAP indications SEI messageis an SEI message that indicates the constraints on picture order and picture referencing used to ensure the decoder can select any EDRAP picture for random access and successfully decode the selected EDRAP picture using only the corresponding reference picture (e.g., in the external bitstream). The EDRAP indications SEI messageincludes an edrap_leading_pictures_decodable_flagsyntax element, which contains a value that indicates whether a set of ordering constraints applies to an EDRAP picture corresponding to the EDRAP indications SEI message.

135 The presence of the EDRAP indications SEI messageplaces certain constraints on EDRAP picture order in a bitstream. For example, each EDRAP picture is a trailing picture. Further, each EDRAP picture has a temporal sublayer identifier equal to zero. Temporal sublayers split pictures into a base layer and one or more enhancement layers. A decoder with lesser capabilities can decode and display the base layer for a lower frame rate, while decoders with greater capabilities can decode increasing numbers of enhancement layers to obtain greater frame rates. Limiting the temporal sublayer identifier to zero ensures the EDRAP picture is in the base layer and is therefore usable by all decoders. Another constraint requires that each EDRAP picture does not include any pictures in a same layer in active entries of a reference picture list of the EDRAP pictures except the list of referenceable pictures. The list of referenceable pictures includes TRAP and/or EDRAP pictures in decoding order. Accordingly, this constraint limits EDRAP pictures to only reference preceding IRAP and EDRAP pictures. Yet another constraint requires that any picture that is in a same layer as an EDRAP picture and that follows the EDRAP picture in both decoding order and output order does not include, in active entries of a reference picture list of the picture, any other picture that is in the same layer and precedes the EDRAP picture in decoding order or output order with the exception of the list of referenceable pictures. This constraint prevents pictures that trail the EDRAP picture from referencing pictures that precede the EDRAP picture. In the event of random access at the EDRAP picture, the preceding pictures would not be available, and hence referencing such pictures by a trailing picture would result in an error due to unavailable reference pictures.

146 The edrap_leading_pictures_decodable_flagsyntax element can place additional constraints on the EDRAP picture. A first of such additional constraints specifies that any picture that is in a same layer as the EDRAP picture and that follows the EDRAP picture in decoding order shall follow, in output order, any other picture that is in the same layer as the EDRAP picture and that precedes the EDRAP picture in decoding order. In some instances, coding order and output order are different. This allows for better compression in some cases, but requires that the pictures be reordered before display. Pictures that follow a random access point in decoding order and preceding the random access point in output order are known as leading pictures. This constraint ensures that leading pictures of the EDRAP picture are not placed in front of trailing pictures from a previous EDRAP picture in output order.

A second of such additional constraints specifies that any picture that is in a same layer as the EDRAP picture, that follows the EDRAP picture in decoding order, and that precedes the EDRAP picture in output order shall not include, in active entries of a reference picture list of the picture, any other picture that is in the same layer as the EDRAP picture and that precedes the EDRAP picture in decoding order, with an exception of a list of referenceable pictures. This constraint ensures that leading pictures only reference pictures following the EDRAP picture and TRAP and/or EDRAP pictures in the list of referenceable pictures. This ensures the leading pictures can be decoded when a corresponding EDRAP picture is used for random access.

141 142 143 144 145 146 As noted above, the value ranges, descriptors, and/or semantics of the ar_object_label_idx[ar_object_idx[i]], the depth_nonlinear_representation_model [i], the depth_nonlinear_representation_num_minus1, the depth_representation_type, the disparity ref_view_id, and the edrap_leading_pictures_decodable_flagare not specified in some example systems. As such, the present disclosure includes such value ranges, descriptors, and/or semantics for the preceding parameters/syntax elements. This allows a decoder to correctly interpret these values without experiencing undefined behavior such as glitches and/or crashes.

141 142 1 143 144 145 146 It should be noted that the ar_object_label_idx[ar_object_idx[i]], the depth_nonlinear_representation_model [i], the depth_nonlinear_representation_num_minus, the depth_representation_type, the disparity ref_view_id, and the edrap_leading_pictures_decodable_flagcan be associated with a descriptor that indicates a coding mechanism used to code the corresponding syntax element. Such descriptors may include ue(v), u(N), se(v), and u(v). ue(v) indicates a syntax element value is coded as an unsigned integer exponential-Golomb coded syntax element with a left bit first and a variable number of bits. Exponential-Golomb code syntax includes representing a value in plus one binary and representing leading zeros as a leading value in minus one format. u(N) indicates a syntax element value is coded as an unsigned integer using N bits. se(v) indicates a syntax element value is coded as a signed integer exponential-Golomb coded syntax element with the left bit first and a variable number of bits. u(v) indicates a syntax element value is coded as an unsigned integer using a variable number of bits.

To solve the above problems, and others, methods as summarized below are disclosed. The items should be considered as examples to explain the general concepts and should not be interpreted in a narrow way. Furthermore, these items can be applied individually or combined in any manner

141 141 In one example, to solve at least one of the problems listed above, the value of the ar_object_label_idx[ar_object_idx[i]]syntax element is specified to be in the range of N to M, inclusive, where N and M are integer values and N is less than M. In one example, N=0 and M=255. In an example, the value of ar_object_label_idx[ar_object_idx[i]]is specified to be in a different range, such as 0 to 3 inclusive, 0 to 7 inclusive, 0 to 15 inclusive, 0 to 31 inclusive, 0 to 63 inclusive, etc.

142 In one example, to solve at least one of the problems listed above, the depth_nonlinear_representation_model[i]syntax element is specified to be ue(v)-coded.

142 142 In one example, the value of depth_nonlinear_representation_model[i]is specified to be in the range of N to M, such as N=0 and M=65535, inclusive. In an example, the value of depth_nonlinear_representation_model[i]is specified to be in a different range, such as 0 to 3 inclusive, 0 to 7 inclusive, 0 to 15 inclusive, 0 to 31 inclusive, 0 to 63 inclusive, 0 to 127 inclusive, 0 to 255 inclusive, 0 to 511 inclusive, 0 to 1023 inclusive, 0 to 2047 inclusive, 0 to 4095 inclusive, 0 to 8191 inclusive, 0 to 16383 inclusive, etc.

142 142 142 142 In one example, the depth_nonlinear_representation_model[i]syntax element is specified to be coded using a different coding method. In one example, the depth_nonlinear_representation_model[i]syntax element is specified to be u(N)-coded, with N equal to a positive integer value, such as a value in the range of 2 to 16, inclusive. In another example, the depth_nonlinear_representation_model[i]syntax element is specified to be se(v)-coded. In another example, the depth_nonlinear_representation_model[i]syntax element is specified to be u(v)-coded, with the length, in units of bits, being specified, for example to be equal to Log 2(MaxNumModes) with the variable MaxNumModes indicating the maximum number of modes and the function Log 2(x) returning the base-2 logarithm of x.

143 In one example, the depth_nonlinear_representation_num_minus1syntax element is specified to be coded using a different coding method from the ue(v) coding method, such as u(N), u(v), etc.

144 144 In one example, to solve at least one of the problems listed above, the value of depth_representation_typeis specified to be in the range of N to M, inclusive, where N and M are integer values and N is less than M. In one example, N=0 and M=15. In one example, the value of depth_representation_typeis specified to be in a different range, such as 0 to 3 inclusive, 0 to 7 inclusive, 0 to 31 inclusive, 0 to 63 inclusive, 0 to 127 inclusive, 0 to 255 inclusive, etc.

143 143 In one example, to solve at least one of the problems listed above, the value of depth_nonlinear_representation_num_minus1is specified to be in the range of 0 to 62, inclusive. In one example, the value of depth_nonlinear_representation_num_minusis specified to be in a different range, such as 0 to 6 inclusive, 0 to 14 inclusive, 0 to 30 inclusive, 0 to 126 inclusive, 0 to 254 inclusive, etc.

145 145 In one example, to solve at least one of the problems listed above, the value of disparity ref_view_idis specified to be in the range of 0 to 1023, inclusive. In one example, the value of disparity_ref_view_idis specified to be in a different range, such as 0 to 63 inclusive, 0 to 127 inclusive, 0 to 255 inclusive, 0 to 511 inclusive, 0 to 2047 inclusive, 0 to 4095 inclusive, 0 to 8191 inclusive, 0 to 16383 inclusive, 0 to 32767 inclusive, 0 to 65535 inclusive, etc.

146 146 146 In one example, to solve at least one of the problems listed above, the semantics of the edrap_leading_pictures_decodable_flagsyntax element is specified as follows. edrap_leading_pictures_decodable_flagequal to 1 specifies that both of the following constraints apply. Any picture that is in the same layer and follows the EDRAP picture in decoding order shall follow, in output order, any picture that is in the same layer and precedes the EDRAP picture in decoding order. Any picture that is in the same layer and follows the EDRAP picture in decoding order and precedes the EDRAP picture in output order shall not include, in the active entries of its reference picture lists, any picture that is in the same layer and precedes the EDRAP picture in decoding order, with the exception of the referenceablePictures. edrap_leading_pictures_decodable_flagequal to 0 does not impose such constraints.

An embodiment of the preceding examples is now described. This embodiment can be applied to VSEI. Relative to the VSEI specification, most relevant parts that have been added or modified are shown in bold underline font, and some of the deleted parts are shown in bold italics fonts. There may be some other changes that are editorial in nature and thus not highlighted.

An example annotated regions SEI message semantics is as follows. The annotated regions SEI message carries parameters that identify annotated regions using bounding boxes representing the size and location of identified objects.

. . .

ar_object_label_idx[ar_object_idx[i]] indicates the index of the label corresponding to the ar_object_idx[i]-th object. When ar_object_label_idx[ar_object_idx[i]] is not present, its value is inferred from a previous annotated regions SEI messages in output order in the same CVS, if any. The value of ar_object_label_idx[ar_object_idx[i]] shall be in the range of 0 to 255, inclusive.

Depth representation information SEI message syntax

De- scriptor depth_representation_info( payloadSize ) {  z_near_flag u(1)  z_far_flag u(1)  d_min_flag u(1)  d_max_flag u(1)  depth_representation_type ue(v)  if( d_min_flag | | d_max_flag )   disparity_ref_view_id ue(v)  if( z_near_flag )   depth_rep_info_element( ZNearSign, ZNearExp, ZNearMantissa, ZNearManLen )  if( z_far_flag )   depth_rep_info_element( ZFarSign, ZFarExp,   ZFarMantissa, ZFarManLen )  if( d_min_flag )   depth_rep_info_element( DMinSign, DMinExp, DMinMantissa, DMinManLen )  if( d_max_flag )   depth_rep_info_element( DMaxSign, DMaxExp, DMaxMantissa, DMaxManLen )  if( depth_representation_type = = 3 ) {   depth_nonlinear_representation_num_minus1 ue(v)   for( i = 1; i <=   depth_nonlinear_representation_num_minus1 + 1; i++ )    depth_nonlinear_representation_model[ i ] ue(v)  } }

An example depth representation information SEI message semantics is as follows. The syntax elements in the depth representation information (DRI) SEI message specify various parameters for auxiliary pictures of type AUX_DEPTH for the purpose of processing decoded primary and auxiliary pictures prior to rendering on a 3D display, such as view synthesis. Specifically, depth or disparity ranges for depth pictures are specified.

A depth_representation_type specifies the representation definition of decoded luma samples of auxiliary pictures as specified in Table Y1. In Table Y1, disparity specifies the horizontal displacement between two texture views and Z value specifies the distance from a camera. The value of depth_representation_type shall be in the range of 0 to 15, inclusive. The variable maxVal is set equal to (1«BitDepthY)−1.

TABLE Y1 Definition of depth_representation_type depth_representation_type Interpretation 0 Each decoded luma sample value of an auxiliary picture represents an inverse of Z value that is uniformly quantized into the range of 0 to maxVal, inclusive. When z_far_flag is equal to 1, the luma sample value equal to 0 represents the inverse of ZFar (specified below). When z_near_flag is equal to 1, the luma sample value equal to maxVal represents the inverse of ZNear (specified below). 1 Each decoded luma sample value of an auxiliary picture represents disparity that is uniformly quantized into the range of 0 to maxVal, inclusive. When d_min_flag is equal to 1, the luma sample value equal to 0 represents DMin (specified below). When d_max_flag is equal to 1, the luma sample value equal to maxVal represents DMax (specified below). 2 Each decoded luma sample value of an auxiliary picture represents a Z value uniformly quantized into the range of 0 to maxVal, inclusive. When z_far_flag is equal to 1, the luma sample value equal to 0 corresponds to ZFar (specified below). When z_near_flag is equal to 1, the luma sample value equal to maxVal represents ZNear (specified below). 3 Each decoded luma sample value of an auxiliary picture represents a nonlinearly mapped disparity, normalized in range from 0 to maxVal, as specified by depth_nonlinear_representation_num_minus1 and depth_nonlinear_representation_model[ i ]. When d_min_flag is equal to 1, the luma sample value equal to 0 represents DMin (specified below). When d_max_flag is equal to 1, the luma sample value equal to maxVal represents DMax (specified below). Other values Reserved for future use

A disparity_ref_view_id specifies the Viewld value against which the disparity values are derived. The value of disparity_ref_view_id shall be in the range of 0 to 1023, inclusive. disparity ref_view_id is present only if d_min_flag is equal to 1 or d_max_flag is equal to 1 and is useful for depth_representation_type values equal to 1 and 3. The variables in the x column of Table Y2 are derived from the respective variables in the s, e, n and v columns of Table Y2 as follows. If the value of e is in the range of 0 to 127, exclusive, x is set equal to (−1)s * 2e — 31 * (1+n÷2v). Otherwise (e is equal to 0), x is set equal to (−1)s*2−(30+v)*n.

TABLE Y2 Association between depth parameter variables and syntax elements x s e n v ZNear ZNearSign ZNearExp ZNearMantissa ZNearManLen ZFar ZFarSign ZFarExp ZFarMantissa ZFarManLen DMax DMaxSign DMaxExp DMaxMantissa DMaxManLen DMin DMinSign DMinExp DMinMantissa DMinManLen

The DMin and DMax values, when present, are specified in units of a luma sample width of the coded picture with Viewld equal to Viewld of the auxiliary picture. The units for the ZNear and ZFar values, when present, are identical but unspecified.

depth_nonlinear_representation_num_minus 1 plus 2 specifies the number of piece-wise linear segments for mapping of depth values to a scale that is uniformly quantized in terms of disparity. The value of depth_nonlinear_representation_num_minus 1 shall be in the range of 0 to 62, inclusive. depth_nonlinear_representation_model[i] for i ranging from 0 to depth_nonlinear_representation_num_minus 1+2, inclusive, specify the piece-wise linear segments for mapping of decoded luma sample values of an auxiliary picture to a scale that is uniformly quantized in terms of disparity. The value of depth_nonlinear_representation_model[i] shall be in the range of 0 to 65 535, inclusive. The values of depth_nonlinear_representation_model[0] and depth_nonlinear_representation_model[depth_nonlinear_representation_num_minus 1+2] are both inferred to be equal to 0.

. . .

An example extended DRAP indication SEI message semantics is as follows. The picture associated with an extended DRAP (EDRAP) indication SEI message is referred to as an EDRAP picture. The presence of the EDRAP indication SEI message indicates that the constraints on picture order and picture referencing specified in this subclause apply. These constraints can enable a decoder to properly decode the EDRAP picture and the pictures that are in the same layer and follow it in both decoding order and output order without needing to decode any other pictures in the same layer except the list of pictures referenceablePictures, which includes a list of TRAP or EDRAP pictures in decoding order that are within the same CLVS and identified by the edrap_ref_rapid[i] syntax elements.

The constraints indicated by the presence of the EDRAP indication SEI message, which shall all apply, are as follows. The EDRAP picture is a trailing picture. The EDRAP picture has a temporal sublayer identifier equal to 0. The EDRAP picture does not include any pictures in the same layer in the active entries of its reference picture lists except the referenceablePictures. Any picture that is in the same layer and follows the EDRAP picture in both decoding order and output order does not include, in the active entries of its reference picture lists, any picture that is in the same layer and precedes the EDRAP picture in decoding order or output order, with the exception of the referenceablePictures.

When edrap_leading_pictures_decodable_flag is equal to 1, the following applies. Any picture that is in the same layer and follows the EDRAP picture in decoding order shall follow, in output order, any picture that is in the same layer and precedes the EDRAP picture in decoding order. Any picture that is in the same layer and follows the EDRAP picture in decoding order and precedes the EDRAP picture in output order does not include, in the active entries of its reference picture lists, any picture that is in the same layer and precedes the EDRAP picture in decoding order, with the exception of the referenceablePictures.

Any picture in the list referenceablePictures does not include, in the active entries of its reference picture lists, any picture that is in the same layer and is not a picture at an earlier position in the list referenceablePictures. Consequently, the first picture in referenceablePictures, even when it is an EDRAP picture instead of an TRAP picture, does not include any picture from the same layer in the active entries of its reference picture lists.

An edrap_rap_id_minus1 plus 1 specifies the RAP picture identifier, denoted as RapPicId, of the EDRAP picture. Each TRAP or EDRAP picture is associated with a RapPicId value. The RapPicId value for an TRAP picture is inferred to be equal to 0. The RapPicId values for any two EDRAP pictures associated with the same TRAP picture shall be different.

An edrap_leading_pictures_decodable_flag equal to 1 specifies that both of the following constraints apply. Any picture that is in the same layer and follows the EDRAP picture in decoding order shall follow, in output order, any picture that is in the same layer and precedes the EDRAP picture in decoding order. Any picture that is in the same layer and follows the EDRAP picture in decoding order and precedes the EDRAP picture in output order shall not include, in the active entries of its reference picture lists, any picture that is in the same layer and precedes the EDRAP picture in decoding order, with the exception of the referenceablePictures. An edrap_leading_pictures_decodable_flag equal to 0 does not impose such constraints.

An edrap_reserved_zero_12bits shall be equal to 0 in bitstreams conforming to this version of this Specification. Other values for edrap_reserved_zero_12bits are reserved. Decoders shall ignore the value of edrap_reserved_zero_12bits. An edrap_num_ref rap_pics_minus1 plus 1 indicates the number of IRAP or EDRAP pictures that are within the same CLVS as the EDRAP picture and may be included in the active entries of the reference picture lists of the EDRAP picture. An edrap_ref_rapid[i] indicates RapPicId of the i-th RAP picture that may be included in the active entries of the reference picture lists of the EDRAP picture. The i-th RAP picture shall be either the IRAP picture associated with the current EDRAP picture or an EDRAP picture associated with the same IRAP picture as the current EDRAP picture.

2 FIG. 4000 4000 4000 4002 4002 is a block diagram showing an example video processing systemin which various techniques disclosed herein may be implemented. Various implementations may include some or all of the components of the system. The systemmay include inputfor receiving video content. The video content may be received in a raw or uncompressed format, e.g., 8 or 10 bit multi-component pixel values, or may be in a compressed or encoded format. The inputmay represent a network interface, a peripheral bus interface, or a storage interface. Examples of network interface include wired interfaces such as Ethernet, passive optical network (PON), etc. and wireless interfaces such as wireless fidelity (Wi-Fi) or cellular interfaces.

4000 4004 4004 4002 4004 4004 4006 4002 4008 4010 The systemmay include a coding componentthat may implement the various coding or encoding methods described in the present disclosure. The coding componentmay reduce the average bitrate of video from the inputto the output of the coding componentto produce a coded representation of the video. The coding techniques are therefore sometimes called video compression or video transcoding techniques. The output of the coding componentmay be either stored, or transmitted via a communication connected, as represented by the component. The stored or communicated bitstream (or coded) representation of the video received at the inputmay be used by a componentfor generating pixel values or displayable video that is sent to a display interface. The process of generating user-viewable video from the bitstream representation is sometimes called video decompression. Furthermore, while certain video processing operations are referred to as “coding” operations or tools, it will be appreciated that the coding tools or operations are used at an encoder and corresponding decoding tools or operations that reverse the results of the coding will be performed by a decoder.

Examples of a peripheral bus interface or a display interface may include universal serial bus (USB) or high definition multimedia interface (HDMI) or Displayport, and so on. Examples of storage interfaces include serial advanced technology attachment (SATA), peripheral component interconnect (PCI), integrated drive electronics (IDE) interface, and the like. The techniques described in the present disclosure may be embodied in various electronic devices such as mobile phones, laptops, smartphones or other devices that are capable of performing digital data processing and/or video display.

3 FIG. 4100 4100 4100 4100 4102 4104 4106 4102 4104 4106 4106 4102 is a block diagram of an example video processing apparatus. The apparatusmay be used to implement one or more of the methods described herein. The apparatusmay be embodied in a smartphone, tablet, computer, Internet of Things (IoT) receiver, and so on. The apparatusmay include one or more processors, one or more memoriesand video processing circuitry. The processor(s)may be configured to implement one or more methods described in the present disclosure. The memory (memories)may be used for storing data and code used for implementing the methods and techniques described herein. The video processing circuitrymay be used to implement, in hardware circuitry, some techniques described in the present disclosure. In some embodiments, the video processing circuitrymay be at least partly included in the processor, e.g., a graphics co-processor.

4 FIG. 4200 4200 4202 is a flowchart for an example methodof video processing. The methodincludes determining a value of an edrap_leading_pictures_decodable_flag syntax element at step. The bitstream comprises at least one EDRAP picture. In an example, the value of the edrap_leading_pictures_decodable_flag indicates whether ordering constraints are imposed on the EDRAP picture. The ordering constraints may not be imposed on the EDRAP picture when the value of the edrap_leading_pictures_decodable_flag is zero. The ordering constraints may be imposed on the EDRAP picture when the value of the edrap_leading_pictures_decodable_flag is one. The constraints may specify that any picture that is in a same layer as the EDRAP picture and that follows the EDRAP picture in decoding order shall follow, in output order, any other picture that is in the same layer as the EDRAP picture and that precedes the EDRAP picture in decoding order. The constraints may further specify that any picture that is in a same layer as the EDRAP picture, that follows the EDRAP picture in decoding order, and that precedes the EDRAP picture in output order shall not include, in active entries of a reference picture list of the picture, any other picture that is in the same layer as the EDRAP picture and that precedes the EDRAP picture in decoding order, with an exception of a list of referenceable pictures.

In an example, the edrap_leading_pictures_decodable_flag syntax element is included in an EDRAP SEI message. In an example, the list of referenceable pictures includes TRAP or EDRAP pictures in decoding order that are within a same CLVS. In an example, each picture in the list of referenceable pictures is identified by an edrap_ref_rapid[i] syntax element. In an example, the edrap_leading_pictures_decodable_flag syntax element is u(v)-coded.

In an example, the EDRAP SEI message specifies additional constraints. In an example, the additional constraints include each EDRAP picture is a trailing picture. In an example, the additional constraints include each EDRAP picture has a temporal sublayer identifier equal to zero. In an example, the additional constraints include each EDRAP picture does not include any pictures in a same layer in active entries of a reference picture list of the EDRAP pictures except the list of referenceable pictures. In an example, the additional constraints include that the bitstream is constrained such that any picture that is in a same layer as the EDRAP picture and that follows the EDRAP picture in both decoding order and output order does not include, in active entries of a reference picture list of the picture, any other picture that is in the same layer and precedes the EDRAP picture in decoding order or output order with the exception of the list of referenceable pictures.

4204 4200 4200 At step, a conversion is performed between a visual media data and a bitstream based on the edrap_leading_pictures_decodable_flag syntax element. When the methodis performed on an encoder, the conversion includes encoding the visual media data into the bitstream. When the methodis performed on a decoder, the conversion includes decoding the visual media data from the bitstream.

4200 4400 4500 4600 4200 4200 4200 It should be noted that the methodcan be implemented in an apparatus for processing video data comprising a processor and a non-transitory memory with instructions thereon, such as video encoder, video decoder, and/or encoder. In such a case, the instructions upon execution by the processor, cause the processor to perform the method. Further, the methodcan be performed by a non-transitory computer readable medium comprising a computer program product for use by a video coding device. The computer program product comprises computer executable instructions stored on the non-transitory computer readable medium such that when executed by a processor cause the video coding device to perform the method.

5 FIG. 4300 4300 4310 4320 4310 4320 4310 is a block diagram that illustrates an example video coding systemthat may utilize the techniques of this disclosure. The video coding systemmay include a source deviceand a destination device. Source devicegenerates encoded video data which may be referred to as a video encoding device. Destination devicemay decode the encoded video data generated by source devicewhich may be referred to as a video decoding device.

4310 4312 4314 4316 4312 4314 4312 4316 4320 4316 4330 4340 4320 Source devicemay include a video source, a video encoder, and an input/output (I/O) interface. Video sourcemay include a source such as a video capture device, an interface to receive video data from a video content provider, and/or a computer graphics system for generating video data, or a combination of such sources. The video data may comprise one or more pictures. Video encoderencodes the video data from video sourceto generate a bitstream. The bitstream may include a sequence of bits that form a coded representation of the video data. The bitstream may include coded pictures and associated data. The coded picture is a coded representation of a picture. The associated data may include sequence parameter sets, picture parameter sets, and other syntax structures. I/O interfacemay include a modulator/demodulator (modem) and/or a transmitter. The encoded video data may be transmitted directly to destination devicevia I/O interfacethrough network. The encoded video data may also be stored onto a storage medium/serverfor access by destination device.

4320 4326 4324 4322 4326 4326 4310 4340 4324 4322 4322 4320 4320 Destination devicemay include an I/O interface, a video decoder, and a display device. I/O interfacemay include a receiver and/or a modem. I/O interfacemay acquire encoded video data from the source deviceor the storage medium/server. Video decodermay decode the encoded video data. Display devicemay display the decoded video data to a user. Display devicemay be integrated with the destination device, or may be external to destination device, which can be configured to interface with an external display device.

4314 4324 Video encoderand video decodermay operate according to a video compression standard, such as the High Efficiency Video Coding (HEVC) standard, Versatile Video Coding (VVC) standard and other current and/or further standards.

6 FIG. 5 FIG. 4400 4314 4300 4400 4400 4400 is a block diagram illustrating an example of video encoder, which may be video encoderin the systemillustrated in. Video encodermay be configured to perform any or all of the techniques of this disclosure. The video encoderincludes a plurality of functional components. The techniques described in this disclosure may be shared among the various components of video encoder. In some examples, a processor may be configured to perform any or all of the techniques described in this disclosure.

4400 4401 4402 4403 4404 4405 4406 4407 4408 4409 4410 4411 4412 4413 4414 The functional components of video encodermay include a partition unit, a prediction unitwhich may include a mode select unit, a motion estimation unit, a motion compensation unit, an intra prediction unit, a residual generation unit, a transform processing unit, a quantization unit, an inverse quantization unit, an inverse transform unit, a reconstruction unit, a buffer, and an entropy encoding unit.

4400 4402 In other examples, video encodermay include more, fewer, or different functional components. In an example, prediction unitmay include an intra block copy (IBC) unit. The IBC unit may perform prediction in an IBC mode in which at least one reference picture is a picture where the current video block is located.

4404 4405 4400 Furthermore, some components, such as motion estimation unitand motion compensation unitmay be highly integrated, but are represented in the example of video encoderseparately for purposes of explanation.

4401 4400 4500 Partition unitmay partition a picture into one or more video blocks. Video encoderand video decodermay support various video block sizes.

4403 4407 4412 4403 4403 Mode select unitmay select one of the coding modes, intra or inter, e.g., based on error results, and provide the resulting intra or inter coded block to a residual generation unitto generate residual block data and to a reconstruction unitto reconstruct the encoded block for use as a reference picture. In some examples, mode select unitmay select a combination of intra and inter prediction (CIIP) mode in which the prediction is based on an inter prediction signal and an intra prediction signal. Mode select unitmay also select a resolution for a motion vector (e.g., a sub-pixel or integer pixel precision) for the block in the case of inter prediction.

4404 4413 4405 4413 To perform inter prediction on a current video block, motion estimation unitmay generate motion information for the current video block by comparing one or more reference frames from bufferto the current video block. Motion compensation unitmay determine a predicted video block for the current video block based on the motion information and decoded samples of pictures from bufferother than the picture associated with the current video block.

4404 4405 Motion estimation unitand motion compensation unitmay perform different operations for a current video block, for example, depending on whether the current video block is in an I slice, a P slice, or a B slice.

4404 4404 4404 4404 4405 In some examples, motion estimation unitmay perform uni-directional prediction for the current video block, and motion estimation unitmay search reference pictures of list 0 or list 1 for a reference video block for the current video block. Motion estimation unitmay then generate a reference index that indicates the reference picture in list 0 or list 1 that contains the reference video block and a motion vector that indicates a spatial displacement between the current video block and the reference video block. Motion estimation unitmay output the reference index, a prediction direction indicator, and the motion vector as the motion information of the current video block. Motion compensation unitmay generate the predicted video block of the current block based on the reference video block indicated by the motion information of the current video block.

4404 4404 4404 4404 4405 In other examples, motion estimation unitmay perform bi-directional prediction for the current video block, motion estimation unitmay search the reference pictures in list 0 for a reference video block for the current video block and may also search the reference pictures in list 1 for another reference video block for the current video block. Motion estimation unitmay then generate reference indexes that indicate the reference pictures in list 0 and list 1 containing the reference video blocks and motion vectors that indicate spatial displacements between the reference video blocks and the current video block. Motion estimation unitmay output the reference indexes and the motion vectors of the current video block as the motion information of the current video block. Motion compensation unitmay generate the predicted video block of the current video block based on the reference video blocks indicated by the motion information of the current video block.

4404 4404 4404 4404 In some examples, motion estimation unitmay output a full set of motion information for decoding processing of a decoder. In some examples, motion estimation unitmay not output a full set of motion information for the current video. Rather, motion estimation unitmay signal the motion information of the current video block with reference to the motion information of another video block. For example, motion estimation unitmay determine that the motion information of the current video block is sufficiently similar to the motion information of a neighboring video block.

4404 4500 In one example, motion estimation unitmay indicate, in a syntax structure associated with the current video block, a value that indicates to the video decoderthat the current video block has the same motion information as another video block.

4404 4500 In another example, motion estimation unitmay identify, in a syntax structure associated with the current video block, another video block and a motion vector difference (MVD). The motion vector difference indicates a difference between the motion vector of the current video block and the motion vector of the indicated video block. The video decodermay use the motion vector of the indicated video block and the motion vector difference to determine the motion vector of the current video block.

4400 4400 As discussed above, video encodermay predictively signal the motion vector. Two examples of predictive signaling techniques that may be implemented by video encoderinclude advanced motion vector prediction (AMVP) and merge mode signaling.

4406 4406 4406 Intra prediction unitmay perform intra prediction on the current video block. When intra prediction unitperforms intra prediction on the current video block, intra prediction unitmay generate prediction data for the current video block based on decoded samples of other video blocks in the same picture. The prediction data for the current video block may include a predicted video block and various syntax elements.

4407 Residual generation unitmay generate residual data for the current video block by subtracting the predicted video block(s) of the current video block from the current video block. The residual data of the current video block may include residual video blocks that correspond to different sample components of the samples in the current video block.

4407 In other examples, there may be no residual data for the current video block for the current video block, for example in a skip mode, and residual generation unitmay not perform the subtracting operation.

4408 Transform processing unitmay generate one or more transform coefficient video blocks for the current video block by applying one or more transforms to a residual video block associated with the current video block.

4408 4409 After transform processing unitgenerates a transform coefficient video block associated with the current video block, quantization unitmay quantize the transform coefficient video block associated with the current video block based on one or more quantization parameter (QP) values associated with the current video block.

4410 4411 4412 4402 4413 Inverse quantization unitand inverse transform unitmay apply inverse quantization and inverse transforms to the transform coefficient video block, respectively, to reconstruct a residual video block from the transform coefficient video block. Reconstruction unitmay add the reconstructed residual video block to corresponding samples from one or more predicted video blocks generated by the prediction unitto produce a reconstructed video block associated with the current block for storage in the buffer.

4412 After reconstruction unitreconstructs the video block, the loop filtering operation may be performed to reduce video blocking artifacts in the video block.

4414 4400 4414 4414 Entropy encoding unitmay receive data from other functional components of the video encoder. When entropy encoding unitreceives the data, entropy encoding unitmay perform one or more entropy encoding operations to generate entropy encoded data and output a bitstream that includes the entropy encoded data.

7 FIG. 5 FIG. 4500 4324 4300 4500 4500 4500 is a block diagram illustrating an example of video decoderwhich may be video decoderin the systemillustrated in. The video decodermay be configured to perform any or all of the techniques of this disclosure. In the example shown, the video decoderincludes a plurality of functional components. The techniques described in this disclosure may be shared among the various components of the video decoder. In some examples, a processor may be configured to perform any or all of the techniques described in this disclosure.

4500 4501 4502 4503 4504 4505 4506 4507 4500 4400 In the example shown, video decoderincludes an entropy decoding unit, a motion compensation unit, an intra prediction unit, an inverse quantization unit, an inverse transformation unit, a reconstruction unit, and a buffer. Video decodermay, in some examples, perform a decoding pass generally reciprocal to the encoding pass described with respect to video encoder.

4501 4501 4502 4502 Entropy decoding unitmay retrieve an encoded bitstream. The encoded bitstream may include entropy coded video data (e.g., encoded blocks of video data). Entropy decoding unitmay decode the entropy coded video data, and from the entropy decoded video data, motion compensation unitmay determine motion information including motion vectors, motion vector precision, reference picture list indexes, and other motion information. Motion compensation unitmay, for example, determine such information by performing the AMVP and merge mode.

4502 Motion compensation unitmay produce motion compensated blocks, possibly performing interpolation based on interpolation filters. Identifiers for interpolation filters to be used with sub-pixel precision may be included in the syntax elements.

4502 4400 4502 4400 Motion compensation unitmay use interpolation filters as used by video encoderduring encoding of the video block to calculate interpolated values for sub-integer pixels of a reference block. Motion compensation unitmay determine the interpolation filters used by video encoderaccording to received syntax information and use the interpolation filters to produce predictive blocks.

4502 Motion compensation unitmay use some of the syntax information to determine sizes of blocks used to encode frame(s) and/or slice(s) of the encoded video sequence, partition information that describes how each macroblock of a picture of the encoded video sequence is partitioned, modes indicating how each partition is encoded, one or more reference frames (and reference frame lists) for each inter coded block, and other information to decode the encoded video sequence.

4503 4504 4501 4505 Intra prediction unitmay use intra prediction modes for example received in the bitstream to form a prediction block from spatially adjacent blocks. Inverse quantization unitinverse quantizes, i.e., de-quantizes, the quantized video block coefficients provided in the bitstream and decoded by entropy decoding unit. Inverse transform unitapplies an inverse transform.

4506 4502 4503 4507 Reconstruction unitmay sum the residual blocks with the corresponding prediction blocks generated by motion compensation unitor intra prediction unitto form decoded blocks. If desired, a deblocking filter may also be applied to filter the decoded blocks in order to remove blockiness artifacts. The decoded video blocks are then stored in buffer, which provides reference blocks for subsequent motion compensation/intra prediction and also produces decoded video for presentation on a display device.

8 FIG. 4600 4600 4600 4602 4604 4606 4602 4604 4606 4606 is a schematic diagram of an example encoder. The encoderis suitable for implementing the techniques of VVC. The encoderincludes three in-loop filters, namely a deblocking filter (DF), a sample adaptive offset (SAO), and an adaptive loop filter (ALF). Unlike the DF, which uses predefined filters, the SAOand the ALFutilize the original samples of the current picture to reduce the mean square errors between the original samples and the reconstructed samples by adding an offset and by applying a finite impulse response (FIR) filter, respectively, with coded side information signaling the offsets and filter coefficients. The ALFis located at the last processing stage of each picture and can be regarded as a tool trying to catch and fix artifacts created by the previous stages.

4600 4608 4610 4608 4610 4612 4614 4616 4618 4618 4616 4620 4622 4624 4624 4602 4604 4606 4612 The encoderfurther includes an intra prediction componentand a motion estimation/compensation (ME/MC) componentconfigured to receive input video. The intra prediction componentis configured to perform intra prediction, while the ME/MC componentis configured to utilize reference pictures obtained from a reference picture bufferto perform inter prediction. Residual blocks from inter prediction or intra prediction are fed into a transform (T) componentand a quantization (Q) componentto generate quantized residual transform coefficients, which are fed into an entropy coding component. The entropy coding componententropy codes the prediction results and the quantized transform coefficients and transmits the same toward a video decoder (not shown). Quantization components output from the quantization componentmay be fed into an inverse quantization (IQ) components, an inverse transform component, and a reconstruction (REC) component. The REC componentis able to output images to the DF, the SAO, and the ALFfor filtering prior to those images being stored in the reference picture buffer. A listing of solutions preferred by some examples is provided next.

The following solutions show examples of techniques discussed herein.

4200 4 FIG. 1. A method of media data processing (e.g., methoddepicted in), comprising: performing a conversion between a video and a bitstream of the video according to a rule, wherein the rule specifies a range for a value of one or more syntax fields indicative of indexes to labels for corresponding objects in an annotated region the video, wherein the range is between N and M, where N and M are integers.

2. The method of solution 1, wherein N=0 and M=255.

3. The method of solution 1, wherein N=0, and M=3.

The following solutions show example embodiments of techniques discussed in the previous section (e.g., item 2).

4. A method of processing video data, comprising: performing a conversion between a video and a bitstream of the video according to a rule, wherein the rule specifies a type of coding used for coding a syntax element indicative of a number of nonlinear segments used in a piecewise nonlinear mapping of depth information for objects in the video is coded in the bitstream.

5. The method of solution 1, wherein the rule specifies that the syntax element is coded as an unsigned integer 0-th order Exp-Golomb-coded syntax element with the left bit first coding.

6. The method of solution 1, wherein the rule specifies that the syntax element is u(N′) coded, where N′ is a positive integer.

7. The method of solution 1, wherein the rule specifies that the syntax element is coded as a signed integer 0-th order Exp-Golomb-coded syntax element with the left bit first.

8. The method of solutions 1-4, wherein the rule specifies that a value of the syntax element is constrained to be within N and M, where N and M are integers.

9. The method of solution 5, wherein N=0 and M=65535.

10. The method of solution 2, wherein N=0, and M=3.

The following solutions show example embodiments of techniques discussed in the previous section (e.g., item 3).

11. A method of processing video data, comprising: performing a conversion between a video and a bitstream of the video according to a rule, wherein the rule specifies a constraint on a syntax element in a supplemental enhancement information syntax structure representing depth information of one or more objects in the video.

12. The method of solution 11, wherein the syntax element includes a depth representation type, and wherein the rule specifies that a value of the syntax element is constrained to be in a range between N and M, where N and M are integers.

13. The method of solution 11, wherein the syntax element indicates a number of nonlinear mapping models for depth information and wherein the rule specifies that the syntax element is in a range between 0 to M, where M is an integer.

14. The method of solution 11, wherein the syntax element indicates an identifier of a disparity reference view, and wherein the rule specifies that a value of the syntax element is between 0 and M, where M is an integer.

The following solutions show example embodiments of techniques discussed in the previous section (e.g., item 4).

15. A method of processing video data, comprising: performing a conversion between a video and a bitstream of the video according to a rule, wherein the rule specifies that a value of a flag indicative of a picture that is an extended dependent random access point controls (1) a first order constraint on pictures in a same layer as the picture and follows the picture in a decoding order and an output order, and (2) a second order constraint on pictures in the same layer as the picture and following the picture in the decoding order and preceding the picture in the output order.

16. The method of solution 15, wherein the value is equal to 1.

17. The method of any of solutions 1-16, wherein the conversion includes generating the bitstream from the video.

18. The method of any of solutions 1-16, wherein the conversion includes generating the video from the bitstream.

19. A video decoding apparatus comprising a processor configured to implement a method recited in one or more of solutions 1 to 18.

20. A video encoding apparatus comprising a processor configured to implement a method recited in one or more of solutions 1 to 18.

21. A computer program product having computer code stored thereon, the code, when executed by a processor, causes the processor to implement a method recited in any of solutions 1 to 18.

22. A method of video processing comprising generating a bitstream according to a method recited in any one or more of solutions 1-8 and storing the bitstream on a computer readable medium.

23. A method, apparatus or system described in the present disclosure.

In the present disclosure, the term “video processing” may refer to video encoding, video decoding, video compression or video decompression. For example, video compression algorithms may be applied during conversion from pixel representation of a video to a corresponding bitstream representation or vice versa. The bitstream representation of a current video block may, for example, correspond to bits that are either co-located or spread in different places within the bitstream, as is defined by the syntax. For example, a macroblock may be encoded in terms of transformed and coded error residual values and also using bits in headers and other fields in the bitstream. Furthermore, during conversion, a decoder may parse a bitstream with the knowledge that some fields may be present, or absent, based on the determination, as is described in the above solutions. Similarly, an encoder may determine that certain syntax fields are or are not to be included and generate the coded representation accordingly by including or excluding the syntax fields from the coded representation.

The disclosed and other solutions, examples, embodiments, modules and the functional operations described in this disclosure can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this disclosure and their structural equivalents, or in combinations of one or more of them. The disclosed and other embodiments can be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a computer readable medium for execution by, or to control the operation of, data processing apparatus. The computer readable medium can be a machine-readable storage device, a machine-readable storage substrate, a memory device, a composition of matter effecting a machine-readable propagated signal, or a combination of one or more them. The term “data processing apparatus” encompasses all apparatus, devices, and machines for processing data, including by way of example a programmable processor, a computer, or multiple processors or computers. The apparatus can include, in addition to hardware, code that creates an execution environment for the computer program in question, e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them. A propagated signal is an artificially generated signal, e.g., a machine-generated electrical, optical, or electromagnetic signal, that is generated to encode information for transmission to suitable receiver apparatus.

A computer program (also known as a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub programs, or portions of code). A computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network.

The processes and logic flows described in this disclosure can be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic circuitry, e.g., a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC).

Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read only memory or a random-access memory or both. The essential elements of a computer are a processor for performing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto optical disks, or optical disks. However, a computer need not have such devices. Computer readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media and memory devices, including by way of example semiconductor memory devices, e.g., erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto optical disks; and compact disc read-only memory (CD ROM) and Digital versatile disc-read only memory (DVD-ROM) disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

While the present disclosure contains many specifics, these should not be construed as limitations on the scope of any subject matter or of what may be claimed, but rather as descriptions of features that may be specific to particular embodiments of particular techniques. Certain features that are described in the present disclosure in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Moreover, the separation of various system components in the embodiments described in the present disclosure should not be understood as requiring such separation in all embodiments.

Only a few implementations and examples are described and other implementations, enhancements and variations can be made based on what is described and illustrated in the present disclosure.

A first component is directly coupled to a second component when there are no intervening components, except for a line, a trace, or another medium between the first component and the second component. The first component is indirectly coupled to the second component when there are intervening components other than a line, a trace, or another medium between the first component and the second component. The term “coupled” and its variants include both directly coupled and indirectly coupled. The use of the term “about” means a range including ±10% of the subsequent number unless otherwise stated.

While several embodiments have been provided in the present disclosure, it should be understood that the disclosed systems and methods might be embodied in many other specific forms without departing from the spirit or scope of the present disclosure. The present examples are to be considered as illustrative and not restrictive, and the intention is not to be limited to the details given herein. For example, the various elements or components may be combined or integrated in another system or certain features may be omitted, or not implemented.

In addition, techniques, systems, subsystems, and methods described and illustrated in the various embodiments as discrete or separate may be combined or integrated with other systems, modules, techniques, or methods without departing from the scope of the present disclosure. Other items shown or discussed as coupled may be directly connected or may be indirectly coupled or communicating through some interface, device, or intermediate component whether electrically, mechanically, or otherwise. Other examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the spirit and scope disclosed herein.